The invention relates to a bearing for the radial and axial support of a rotor having large radial dimensions about a stator.
DE-OS 3,243,641 discloses that mechanical bearings, and electrodynamic magnetic bearings can be employed for rotors having large radial dimensions.
This publication also discloses the control of the tilt axes of a rotor having large radial dimensions in order to, on the one hand, effectively counteract interfering moments and natural frequencies and, on the other hand, generate certain moments which, in the manner of gyroscopic moments, cause the system to swing horizontally.
DE-OS 3,240,809 discloses a magnetic bearing in which the diameter of the air gap is large compared to the axial length of the bearing. The rotor is radially passively mounted by means of permanent magnets at least on the side of the rotor, while the axial position of the rotor is actively regulated by a control device. In order to determine the axial position of the rotor, several sensor arrangements are employed as well as control amplifiers and coils which exert forces on the rotor. Four sensor arrangements are arranged in pairs diametrally to the axis of rotation on mutually perpendicular axes which are also perpendicular to the axis of rotation. Three control amplifiers are provided of which the first and second control amplifier each receive the difference between the sensor signals of diametrally opposite sensor arrangements and the third control amplifier receives the sum of all sensor output signals. The outputs of the control amplifiers are connected with windings in such a manner that actuation of the first and second amplifier causes restoring moments to act on the rotor about the axis perpendicular to the axis on which the associated sensor arrangements are disposed and actuation of the third amplifier causes an axial restoring force to act on the rotor.
Additionally the '809 reference discloses that the input signals of the first and second control amplifier are cross-coupled, that is, part of the input signal of the one amplifier is superposed on the input signal of the other amplifier.